The men wore orange vests bearing the words “Sharia Police”, leading to charges that they had broken a law banning political uniforms that aims to prevent street movements such as the early Nazi party.

A district court in Wuppertal in November 2016 found that the sharia vests did not appear intimidating, noting that one witness had thought the men were part of a bachelor party.

Prosecutors appealed, and the Federal Court of Justice in the city of Karlsruhe Thursday overturned the not-guilty verdicts and sent the case back to the district court.

The higher court cited mistakes, including the fact the district court had not sufficiently established how threatening the vigilantes appeared to other young Muslims.

So-called “sharia patrols” by sometimes violent radical young Salafists have also been seen in other European cities such as London, Copenhagen and Hamburg.